The present invention relates to the field of smokers"" articles.
More precisely the invention relates to the field of such articles using at least one reconstituted tobacco leaf.
Proposals are made in French patent application FR-97/15845 in the name of the Applicant, for an article enabling consumers to prepare their own cigarillos, said article comprising in particular a set of reconstituted tobacco leaves that are interleaved in such a manner as to enable them to be dispensed automatically by pulling on the various leaves in succession.
In such an article, each reconstituted tobacco leaf, also referred to as a xe2x80x9ctobacco leafxe2x80x9d has a stripe of adhesive applied to one of its margins. Once the stripe of adhesive has dried, the leaves are interleaved.
The stripe of adhesive makes it possible, once a leaf has been rolled up, to stick down its margin on the roll formed in this way. The adhesives used for this purpose include, in particular, food grade adhesives enabling the user to stick down the margin with the help of saliva.
With leaves that have been coated with a stripe of food grade adhesive, the adhesive used can either be a cold adhesive deposited at ambient temperature and dried by convection, or a hot adhesive, e.g. a natural gum arabic or a synthetic adhesive that is deposited while hot and is dried by radiation (of the infrared type) that is localized in register with the stripe of adhesive, or else is dried in a convective oven.
The techniques presently used for putting such stripes of adhesive into place are not satisfactory.
In particular, it turns out that the tobacco leaf absorbs the gum to such an extent that the leaf with its stripe of gum has adhesive properties that are poor.
Previously proposed leaves with their stripes of adhesive enable only particularly fragile cigarillos to be made.
A main object of the invention is to propose a reconstituted tobacco leaf where the stripe of adhesive lining one of its margins enables said margin to be secured in satisfactory manner to the remainder of the leaf.
In the context of the present invention, this object is achieved by a reconstituted tobacco leaf coated with a stripe of adhesive along one of its margins, the leaf being characterized in that the linear mass of the stripe of adhesive in the dry state is greater than 70 milligrams per meter (mg/m).
In another aspect, the invention provides a method of applying such a stripe of adhesive on a reconstituted tobacco leaf, whereby the tobacco leaf conserves a certain amount of elasticity after the stripe of adhesive has been put into place. In known methods for applying a stripe of adhesive, the stripe of adhesive is dried in a manner that also leads to the leaf drying and thus becoming brittle. The leaf loses so much strength that it becomes practically impossible to use the leaf to make a smokers"" article in which it needs to be tightly curved.
A method of the invention for applying a stripe of adhesive is a method in which the adhesive is dried by heating the leaf carrying the stripe, and in which the moisture content of the leaf is maintained during drying at greater than 7%.
In a third aspect of the invention, an apparatus is provided for implementing such a method, the apparatus consisting in an oven provided with means for moving the leaves in translation, said means passing through the oven, and having means for spraying water on entry into the oven and at least one air-blowing nozzle which is disposed so as to blow air on the stripe of adhesive.